The wind turbines of Altamont Pass, blades glinting in the afternoon sun, have become a welcome signpost of home for me over the years. As the plane I’m on begins its descent into Oakland, the wind farm – more than the Sierra, more than the flatness of the Central Valley – marks a kind of boundary. Part of it is esthetic, part symbolic: I’m back where clean, renewable energy is taken seriously.

But wind power is not just a California eccentricity any more. Propelled by state policies requiring utilities to purchase more wind energy, a federal production tax credit, and a decrease in manufacturing and construction costs, US wind energy capacity increased by over 40 percent in 2001, and another 10 percent in 2002. The trend has been even stronger in Europe, where 70 percent of the planet’s wind energy is produced, with Germany and Spain the leading players. New facilities are planned or under construction from the Black Sea coast of Bulgaria to South Gippsland in Australia.

Annie Dillard, author of Pilgrim at Tinker Creek and Holy the Firm, has spoken eloquently of the esthetic side of wind power: “Wind farms are beautiful. Silently they witness the winds. Their motion adds value and beauty, as sailboats and kites do. Their fixed bases bespeak fidelity and acceptance, as windmills do.”

There’s another side, though, a reminder that no energy source, however “green,” is without its costs. Five years ago, when Enron’s wind power division proposed building a wind farm near Gorman in the mountains of Southern California, The National Audubon Society’s Vice President Daniel Beard responded: “It is hard to imagine a worse idea than putting a condor Cuisinart next door to critical condor habitat& Enron is proposing to build a death trap.”

There’s no question that wind farms kill birds. And that’s not their only environmental impact: a recent study by S. Baidya Roy at Duke University indicates large windmill arrays could influence local climates, increasing ground-level wind speeds, boosting temperatures by about two degrees Celsius, and drying out the soil. And a broader computer simulation by David Keith at the University of Calgary and Stephen Pacala at Princeton suggests that expanding wind generation to ten percent of today’s North American energy budget would produce cooling in the Arctic and warming across the southern portion of the continent.

So far, though, avian mortality has been the primary concern. Although I’m unaware of any California condor casualties, the death toll has included golden eagles at Altamont, griffon vultures in Spain, migratory songbirds, even bats (4,000 red bats in a single migration season at Backbone Mountain, Virginia). But how grave is the threat, and does the risk of wildlife kills outweigh the potential benefits of this non-fossil-fuel power source? These questions have riven environmental and animal-welfare groups, pitting Greenpeace against the Humane Society, creating internal schisms in other organizations. Each side can claim support from ornithological field studies. The dispute is sure to become more contentious as wind farms proliferate and as wind generation expands from landbased sites to offshore facilities.

What follows is an attempt to provide context for this highly charged issue, and a survey of some of the flash points: the rolling hills of Altamont, the Strait of Gibraltar, the shores of Cape Cod.

In winter, the greening hills around Altamont Pass become prime hunting grounds for birds of prey. Local golden eagles and red-tailed hawks are joined by visitors from the north – ferruginous and rough-legged hawks, the Harlan’s subspecies of the red-tail, northern harriers. I’ve seen over a dozen red-tails strung out along a ridge, each holding station in the wind, watching for rodent movements in the grass below. The Altamont hills are part of a significant raptor migration corridor and home to the highest concentration of golden eagles in North America. Since 1982 those hills have sprouted a metal forest of wind turbines – some 5,400 at latest count – that generate over 600 megawatts of power.

Inevitably, hawks, eagles, and other birds have collided with the turbines’ blades – 881 to 1,300 raptors each year, according to the Center for Biological Diversity (CBD). “Altamont Pass has the worst bird kill problem of any wind facility in North America,” says CBD’s Jeff Miller, pointing out that the wind farms were built without a thorough review of potential avian mortality. Some of the raptors affected are species of conservation concern, or are protected under federal legislation such as the Bald Eagle and Golden Eagle Protection Act and Migratory Bird Treaty Act. The birds may hit the towers in flight, or attempt to use them as roosts or as vantage points from which they scan for prey.

Although over 40 species, including burrowing owls, western meadowlarks, loggerhead shrikes, and the occasional mallard, have been documented as wind turbine victims at Altamont, the majestic golden eagle has received most of the attention. Eagles appear to have declined around the Altamont Pass Wind Resource Area (APWRA) since the wind farms have been in place, according to a 1990s study by Grainger Hunt, an ecologist with the Predatory Bird Research Group of the University of California at Santa Cruz. Hunt’s subsequent research involving radio-tagged eagles found disproportionate mortality among subadult birds and adult “floaters,” rather than breeders with a home territory.

But it’s not universally agreed that windmill mortality was responsible for the decline. Ornithologist Paul Kerlinger, former director of the Cape May Bird Observatory, blames other factors: “A new reservoir destroyed foraging and nesting habitat within the wind resource area; the City of Livermore has pushed its boundaries up against the wind farms; and it is beginning to look like the oak trees that exist outside the wind resource area are not coming back due to cattle grazing. These are the oaks golden eagles nest in. As the trees go, so go the eagles.”

The most recent Altamont study, a massive report prepared by consultants Shawn Smallwood and Carl Thelander for the California Energy Commission and released in 2004, was based on carcass searches at over 4,000 of the APWRA’s turbines. Their conclusion: “Over the past 15 years, the risk to birds of turbine-caused fatalities increased substantially in the APWRA.” They were critical of previous consultant studies whose reliance on the reporting of bird kills by turbine maintenance workers and other methodolgical flaws may have resulted in underestimating mortality.

Smallwood and Thelander found that golden eagle mortality was higher at turbines located in canyons, and that red-tailed hawk deaths reflected concentrations of pocket gophers around the towers. They also discovered that some tower configurations are more lethal than others, with raptor deaths associated more with tubular towers and turbines with larger rotor diameters. Placement seemed to make a difference: isolated turbines killed more birds, while parallel rows of turbines with alternating tower heights were less dangerous. (Hunt’s eagle studies had previously shown that areas with Type-13 turbines, which account for about half the APWRA’s turbines, had the most blade-strike fatalities).

The CEC report offered a menu of suggestions for reducing raptor deaths at Altamont: primarily, replacing the current configuration of many small turbines with fewer but larger towers. Failing that, Smallwood and Thelander recommended removing the most dangerous towers, ending a counterproductive rodent control program that actually increased the clustering of gophers and other prey species under the towers, moving rock piles away from turbines, and choosing safer designs for new towers.

Prior to the release of the Smallwood-Thelander report, CBD had filed suit against the Florida-based FPL Group Inc. and the Danish company NEG Micon A/S for their role in killing protected birds in the APWRA. However, when Federal Judge Claudia Wilkins made it clear that she would limit the scope of the litigation, CBD dropped its suit in August and decided to wait for the wind companies’ response to the CEC report’s recommendations. But that response was disappointing: a draft mitigation plan to be implemented on a volunteer basis on a small percentage of the Altamont turbines, with no shutdown of killer turbines and no commitment to offsite mitigation. The CEC called the plan inadequate, charging that it “does not apply the mitigation measures in the manner recommended by [the report] to directly reduce bird kills.” CBD went back to court in November, this time alleging violations of the California Fish and Game Code and federal legislation by FPL and eight other wind power companies.

If Altamont has the worst bird-kill record in North America, the most controversial wind farm sites in Europe would have to be those in Spain – in Galicia on the Atlantic Coast, in Navarra on the border of Basque country, and at the Strait of Gibraltar, a major concentration point for Africa-bound migrant birds. Mark Duchamp, a Belgian living in Spain, has raised the alarm about raptor deaths at these sites. He points to a 1995 tally of 89 birds, including 14 protected species, killed at two wind farms in Tarifa, on the Strait. He considers this an undercount. Duchamp also reports that a one-year survey by biologist J. M. Leukona at a 400-turbine facility in Navarra found the carcasses of 432 raptors (mostly griffon vultures), 6,152 songbirds and other smaller species, and 671 bats under the towers. Extrapolating this to Spain’s 10,000 existing turbines, Duchamp sees a major threat to endangered resident raptor species such as the Bonelli’s, booted, and short-toed eagles, the lammergeier, and the griffon, black, and Egyptian vultures, as well as migrants.

Other Spanish data is more equivocal. A study by Luis Barrios and Alejandro Rodriguez found that wind farm mortality mainly affected two resident raptor species – the griffon vulture and common kestrel – and that only a small fraction of migrating birds were at risk from turbine collisions. And Alvaro Camina, monitoring the Sierra de la Hez Wind Resource Area in La Rioja province, reported no fatalities during his study period and only one documented death prior to that.

The raptor fatalities at Altamont and the Spanish wind farms have fueled opposition to new facilities elsewhere. BirdLife International has objected to the proposed facility at Balchik, Bulgaria, where 87,000 storks, 9,000 pelicans, and 7,000 raptors pass through a migration bottleneck each year. Environmentalists have opposed Chatauqua Windpower’s proposed project in upstate New York as a threat to nocturnal songbird migrants. But perhaps the hottest debate centers on a new frontier in windpower generation, at least in North America: the offshore wind farm. The battle has been joined on Cape Cod, pitting Cape Wind, the developer, against the local Alliance to Protect Nantucket Sound, and enlisting at least two members of Congress.

Northern Europe has pioneered in offshore wind power development, beginning in 1990 off the Swedish coast; last year there were nine operational offshore wind farms in Europe. But data on their impact on birds and other wildlife is sparse. As of 2003, only three of the European facilities had completed avian impact studies, and only the Danish National Environmental Research Institute had released the results of such a study. Rather than migrant birds, the Danish research focused on two sea ducks, the common eider and black scoter, both of which winter in Danish waters near the Tuno Knob wind farm. No data on bird collisions with the wind towers were presented: findings included a sharp drop in eider and scoter numbers within two years after construction of the facility, but the connection with the wind farm was clouded by a concurrent decline in the local population of blue mussels, the ducks’ preferred prey.

What’s at stake at Cape Cod? Cape Wind’s project is ambitious: the largest turbines manufactured by General Electric, each 417 feet tall with three 50-meter-long blades and a generation potential of seven to ten megawatts. The 130 turbines would cover over 28 square miles in an area of Nantucket Sound called Horseshoe Shoals, six miles from Hyannis and nine miles from Martha’s Vineyard. Proponents claim the wind farm’s output would replace 113 million gallons of oil or 500,000 tons of coal each year.

But the Alliance – supported by Earth Island Institute’s Oceans Public Trust Initiative and the Humane Society of the United States – contends Cape Cod is a dubious place for a massive windpower facility, and that Cape Wind is taking advance of regulatory loopholes and less-than-stringent oversight by the Army Corps of Engineers to push the project through.

It’s not all about wildlife. Unlike Annie Dillard, not all Cape Codders see the visual appeal of wind power arrays. “The viewshed issue is not unimportant,” says the Humane Society’s Sharon Young. “Property values on Cape Cod are astronomical. A median-income family can’t afford to buy a median-priced house. And property owners don’t want to look at turbines.”

Young is quick to point out the unknown effect of the Cape Wind project on birds and marine mammals, though. Nantucket Sound is on the migration path of the northern right whale, and is used regularly by minke, humpback, and fin whales, as well as harbor porpoises. According to ornithologist Ian Nisbet, tens of millions of land birds migrate through the Cape Cod area each fall, and a quarter of a million long-tailed ducks winter at sea southeast of Nantucket, commuting into the Sound’s sheltered waters every evening. About a third of the East Coast’s piping plover population nests on Nantucket, the Vineyard, and adjacent islands.

And then there’s the roseate tern, a federal endangered species. Nisbet has studied these graceful seabirds since 1970 and helped lead their recovery program. It’s because of the roseates, along with the state-listed common tern and the threatened piping plover, that the American Bird Conservancy has designated Cape Cod and the nearby islands as an Important Bird Area. Historically, the terns’ nesting colonies were devastated by plume hunters and eggers, and much of their original coastal habitat has been lost to development. Most of the remaining roseate terns are concentrated in a few colony sites between Long Island and Cape Cod, where they’ve experienced several poorly understood population crashes. In mid-September, after staging around Cape Cod, the terns begin a perilous flight down the Atlantic Coast and across the Caribbean, in hurricane season, to South America. In the Guyanese portion of their winter range, they’re netted by jacklight-equipped market hunters.

In a March 2002 letter to the Corps of Engineers, Ian Nisbet pointed out that roseate and common terns feed, breed, and rest at locations all around the Sound from April through mid-October. In late summer, half the roseate terns in North America roost at night at South Beach in Chatham, flying in from other parts of Nantucket Sound. Nisbet suspects many of these birds cross Horseshoe Shoals, the designated site for the wind farm. Nisbet also suggested, in an article written with Jeffrey Spendelow for the journal Waterbirds, that roseate terns specialize in feeding over shoals, and that their distribution is limited by the availability of suitable shoal habitat.

Cape Wind has downplayed the offshore farm’s potential impact on the terns and other birds in Nantucket Sound. But both the US Fish & Wildlife Service and the Massachusetts Division of Fisheries & Wildlife have been scathingly critical of the company’s data, which relied on Audubon’s Christmas Bird Counts – an all-day, multi-nation census of early-winter bird populations – and winter waterfowl surveys instead of migration studies. In 2001, State Ornithologist Bradford Blodget said his agency was “quite concerned by the magnitude of this proposal, especially in light of the facts that it has essentially no historical precedent and little is known about what effect, if any, the turbines will actually have on all migratory birds.” He noted that roseate tern restoration sites “literally surround the Horseshoe Shoals,” and called for more thorough field studies. Blodget was seconded by FWS Regional Supervisor Michael Bartlett, who called both the studies so far and those proposed by Cape Wind inadequate, since they did not include the remote sensing technology needed to document nocturnal migration.

Ironically, the wildlife agencies have, in fact, taken a stronger position than some environmental groups. National Audubon has been silent, and statements from the independent Massachusetts Audubon Society have been guarded in the extreme. But Massachusetts Audubon’s Jack Clarke did recommend that Important Bird Areas and lands and waters important for endangered species remain off-limits for wind power development. Greenpeace has said it will oppose the project if the Environmental Impact Statement shows significant impact – an unlikely contingency, since the EIS was written by Cape Wind. Gary Skulnick of Greenpeace calls the opposition to the project “a very interesting case of NIMBYism,” noting that no one had complained about two coal-burning power plants nearby. “Wind turbines don’t make a lot of noise,” says Skulnick. “They don’t spew toxic chemicals. If I lived in the area, I would feel great about being on the cutting edge of innovation.”

Apart from the wildlife controversy, there are issues of process and precedent. Cindy Lowry of the Oceans Public Trust Initiative says Cape Wind “is trying to slip through the cracks.” Both the recent federal oceans report and the Pew Commission report (see EIJ Winter 2005) recommended establishing a regulatory framework for offshore projects. Lowry worries that Corps approval of the Cape Cod wind farm could open a Pandora’s box, encouraging problematic aquaculture or Liquefied Natural Gas projects. “There has not been a programmatic environmental impact statement on offshore wind energy,” she says. “The Corps shouldn’t be processing applications in the absence of environmental standards.”

Although the Army Corps of Engineers is only one of 17 state and federal agencies involved in the Cape Wind review process (others include the Federal Aviation Administration and the Environmental Protection Agency), it claims primary jurisdiction based on the antiquated Rivers and Harbors Act, a 19th-century law dealing with navigational hazards on private property. Both Lowry and Young are leery of the close relationship between regulators and developer. The Corps’ draft EIS, delayed by higher-level Pentagon review, was released in November. Young calls it “horrible” and “distressing,” claiming it lowballs the avian impact potential (2.8 birds per turbine per year, reflecting data from land-based facilities), ignores radar migration studies, underestimates marine-mammal impacts, and uses an erroneous definition of “cumulative impacts.”

If approved, Cape Wind could be only the first of a string of Atlantic Coast wind farms. Twenty or more sites from Rhode Island to North Carolina are under consideration. In September, Winergy LLC applied for a permit for five projects off the New Jersey coast, including one off Cape Maysited on a major migration corridor for hawks and songbirds. This prompted US Representative Frank Pallone (D-NJ), whose district includes coastal Monmouth County, to demand a moratorium on offshore wind farm construction until the Corps has “completed a comprehensive assessment of all potential environmental and socioeconomic impacts.”

At the same time, Senator John Warner (R-VA), who chairs the Armed Services Committee, attached an amendment to the pending Defense Authorization Act, which would have frozen the permitting process until Congress approved new regulations for offshore wind development. Cape Wind cried foul: “At a time when Americans are more concerned than ever about our dependence on Mideast oil, with our soldiers dying in Iraq and with record high oil prices, Senator Warner is attempting to block one of America’s options for reducing our dependence on the Middle East – developing clean, offshore, American wind power.” After Republican members of the House also objected, the Warner amendment was dropped.

Young, Lowry, Miller, and other critics of specific wind power projects have made it clear that they don’t oppose wind energy development. But they say they want to see it done right. “We know that when things aren’t done correctly they can come back to haunt you,” Lowry says. “We want the legal and scientific framework in place and agency oversight.” Young agrees with the need for careful risk assessment before new offshore facilities are built: “Let’s not the repeat the mistakes made with terrestrial plants.” She advocates using GIS data to pinpoint high-risk sites so farms won’t be situated “smack in the middle of a migratory corridor.” For the Cape Cod project, she says, “Cape Wind just looked at where the wind was and where the electical grid was” without considering the consequences. And Miller emphasizes that the CBD doesn’t want to shut down the Altamont wind farm, only to force the industry to address the raptor kills and learn from the California experience. “We’re hoping the controversy will ensure that any future siting is done only after a thorough review.”

The wind power issue “is a really tough one for environmental groups,” says Young. “We all believe we need to look at alternative energy technologies for the greatest benefits and least risks. There are no risk-free options, but where we can avoid loss, we need to do that.” The old adage about the nonexistence of free lunches seems to apply. At a minimum, it makes sense to put a regulatory framework for offshore wind energy development in place, to give environmental values more weight in site selection, and to push for risk reduction and mitigation at existing land-based arrays. We need to ensure that there’s still room in our skies for eagles, vultures, and terns – as well as the whirling blades that harness the wind.

— Joe Eaton is a freelance natural history writer and a frequent contributor to Earth Island Journal. He lives in Berkeley.

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